Logic Board - Macintosh SE Reloaded
- Thread starter Kai Robinson
- Start date
Finally got to testing things out. My initial tests were just focused on the jumpers, which appeared to have continuity as expected.
In a conversation with @JDW, I got a little more direction and did some further testing. The results were:
When testing, I did it in either direction, using the red probe on the resistor and then the black--
• Touching either probe to the left side of R35 and on the 1M pin, got a beep
• Touching either probe to the left side of R36 and on the 2/4M pin, got a beep
• As expected, the center pin did nothing.
@callanbrown You indicate that your system crashed upon startup. Was this a bomb when software started to load or a Sad Mac? If it was a Sad Mac, what was the error code thrown? That definitely would be useful to try and help isolate the possible problem.
In a conversation with @JDW, I got a little more direction and did some further testing. The results were:
When testing, I did it in either direction, using the red probe on the resistor and then the black--
• Touching either probe to the left side of R35 and on the 1M pin, got a beep
• Touching either probe to the left side of R36 and on the 2/4M pin, got a beep
• As expected, the center pin did nothing.
@callanbrown You indicate that your system crashed upon startup. Was this a bomb when software started to load or a Sad Mac? If it was a Sad Mac, what was the error code thrown? That definitely would be useful to try and help isolate the possible problem.
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You say the center pin did nothing - this is the problem I had, it should be grounded, not "nothing". there is a center plane in the PCB sandwich that the center pin should be connected to.
So you should continuity check the center pin to a ground pin. See if the two points with arrows gives you a beep.
Before I fixed this problem on my board, I'm pretty sure I was getting vertical lines sometimes on bootup, other times I believe I could get to the desktop before it would freeze. I don't think I got error codes or sad macs.
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Hiya @callanbrown. Alrighty...after some further looking into things, here's what I found:
1. When using a 1MB setup [4x256KB SIMMs]...placed in SIMM1 and SIMM2, with J16 set to the 1MB position - startup chime with vertical lines.
2. When using a 2MB setup [2x1MB] placed in SIMM1 and SIMM2, with J16 set to 2/4M - no startup chime, immediate Sad Mac.
3. When using a 2MB setup [2x1MB] placed in SIMM3 and SIMM4, with J16 set to 2/4M - no startup chime, random screeching from speaker and random lines on the display.
4. When using a 2.5MB setup [2x1MB + 2x256KB] with the 1MB SIMMs in SIMM1 and SIMM2 and the 256KB SIMMs in SIMM3 and SIMM4, with J16 set to 2/4M - startup chime and what appears to be a large smiley face.
5. A 4MB setup with 4x1MB - startup chime, no other issues.
I tested the points you indicated in your last post, Pin 8 of U2F and the center pin of J16, no beep.
@Kai Robinson...for your review.
1. When using a 1MB setup [4x256KB SIMMs]...placed in SIMM1 and SIMM2, with J16 set to the 1MB position - startup chime with vertical lines.
2. When using a 2MB setup [2x1MB] placed in SIMM1 and SIMM2, with J16 set to 2/4M - no startup chime, immediate Sad Mac.
3. When using a 2MB setup [2x1MB] placed in SIMM3 and SIMM4, with J16 set to 2/4M - no startup chime, random screeching from speaker and random lines on the display.
4. When using a 2.5MB setup [2x1MB + 2x256KB] with the 1MB SIMMs in SIMM1 and SIMM2 and the 256KB SIMMs in SIMM3 and SIMM4, with J16 set to 2/4M - startup chime and what appears to be a large smiley face.
5. A 4MB setup with 4x1MB - startup chime, no other issues.
I tested the points you indicated in your last post, Pin 8 of U2F and the center pin of J16, no beep.
@Kai Robinson...for your review.
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I'm looking at the Gerbers and connection to the ground plane is indeed missing. Kai, I DM'd you on Discord about this back in September and you said it was there in Sprint, so maybe the Gerber export screwed up?
In the attachment you can see the three big pins (one is square). The middle should be connected to the ground plane. In the bottom right you can see what a pad connected to a plane looks like.
In the attachment you can see the three big pins (one is square). The middle should be connected to the ground plane. In the bottom right you can see what a pad connected to a plane looks like.
Attachments
Heya @Kai Robinson More detail for your review.
I got my SE put back together after the little ADB fiasco I found myself in. First startup, there was some happiness....a startup chime, followed by an arrow pointer and a disk with a flashing question mark. OK, I thought...we're gonna be good. Then the testing began. Here are those findings:
Floppy related:
• Inserting a floppy disk into the internal floppy drive, connected to the Lower internal connector - the disk immediately was ejected with a flashing
.
• Shut down, changed to the Upper internal connector. Same thing happened -- the disk immediately was ejected with a flashing.
• Shut down again, connected a known good external floppy drive -- another go of the disk immediately being ejected with a flashing.
• Shut down, disconnected the external floppy drive and used a FloppyEMU...the disk remained mounted on the FloppyEMU, disk with flashing
• Shut down, disconnected the FloppyEMU from the external port and connected to the Lower internal connector, same result.
• Shut down, disconnected the FloppyEMU from the Lower internal connector and connected to the Upper internal connector, same result.
The IWM was known to be good before the build began.
The internal floppy drive is connected using a red-striped ribbon cable, the same one that came from the donor machine. I even tried with a yellow-striped cable from a Mac Plus [also known to be good]. As noted above, same results. The floppy drive being used has been recapped, cleaned, lubricated and tested rigorously before reinstallation into the rebuilt SE.
SCSI related:
• When connecting an external hard disk or BlueSCSI to the external connector, there is no activity.
• When connecting a SCSI hard disk or internal BlueSCSI to the internal port, the system boots normally.
The SCSI chip used was an NCR 53C80-40, which in past reading was not known to be an issue. At least on the SCSI bus, there are signs of life.
I used a Hard Disk 20SC for the external drive with System 6.0.8, a known good Apple Quantum 40 from another SE with a known good System 6.0.5 installation. The BlueSCSI card has System 6.0.8.
ADB related:
Using a 'modern replacement' PIC chip...with a keyboard and mouse connected -- the mouse pointer is jumpy and sometimes 'clicks' itself without the button being pressed. The keyboard is responsive at times, others not. Disconnecting and reconnecting the ADB cable will make things work for a moment, then stop again. I did discover that the Bourns filter at U11B was installed backwards [Pin 1 at Pin 10...my bad there]. I fixed that, but the same phenomena still remains.
If there is a list of things to test/check, let me know and I will make it so and report back.
I got my SE put back together after the little ADB fiasco I found myself in. First startup, there was some happiness....a startup chime, followed by an arrow pointer and a disk with a flashing question mark. OK, I thought...we're gonna be good. Then the testing began. Here are those findings:
Floppy related:
• Inserting a floppy disk into the internal floppy drive, connected to the Lower internal connector - the disk immediately was ejected with a flashing
.• Shut down, changed to the Upper internal connector. Same thing happened -- the disk immediately was ejected with a flashing
.• Shut down again, connected a known good external floppy drive -- another go of the disk immediately being ejected with a flashing
.• Shut down, disconnected the external floppy drive and used a FloppyEMU...the disk remained mounted on the FloppyEMU, disk with flashing
• Shut down, disconnected the FloppyEMU from the external port and connected to the Lower internal connector, same result.
• Shut down, disconnected the FloppyEMU from the Lower internal connector and connected to the Upper internal connector, same result.
The IWM was known to be good before the build began.
The internal floppy drive is connected using a red-striped ribbon cable, the same one that came from the donor machine. I even tried with a yellow-striped cable from a Mac Plus [also known to be good]. As noted above, same results. The floppy drive being used has been recapped, cleaned, lubricated and tested rigorously before reinstallation into the rebuilt SE.
SCSI related:
• When connecting an external hard disk or BlueSCSI to the external connector, there is no activity.
• When connecting a SCSI hard disk or internal BlueSCSI to the internal port, the system boots normally.
The SCSI chip used was an NCR 53C80-40, which in past reading was not known to be an issue. At least on the SCSI bus, there are signs of life.
I used a Hard Disk 20SC for the external drive with System 6.0.8, a known good Apple Quantum 40 from another SE with a known good System 6.0.5 installation. The BlueSCSI card has System 6.0.8.
ADB related:
Using a 'modern replacement' PIC chip...with a keyboard and mouse connected -- the mouse pointer is jumpy and sometimes 'clicks' itself without the button being pressed. The keyboard is responsive at times, others not. Disconnecting and reconnecting the ADB cable will make things work for a moment, then stop again. I did discover that the Bourns filter at U11B was installed backwards [Pin 1 at Pin 10...my bad there]. I fixed that, but the same phenomena still remains.
If there is a list of things to test/check, let me know and I will make it so and report back.
Hello chaps! It does indeed look like the Gerber export didn't include that, for whatever reason - here's what i'm seeing in Sprint:
Circled is the middle pin, which is very much connected to the ground plane - luckily, as you pointed out, this is an easy fix - solder a bodge wire to the right hand side of C53, that's the nearest ground plane point. C51 or C52's right hand side will also work.
I'll do a clean export of the sprint original along with the gerbers, put them on GitHub shortly and send this over to Mark @ MacEffects - Revision 1.6b is going to be the CURRENT version, as i've spotted a naming issue with the additional address line tap-point i added for the SMC to do a Classic ROM adapter.
Thank you to everyone for bringing this to my attention - I hate it when issues like this crop up!
Circled is the middle pin, which is very much connected to the ground plane - luckily, as you pointed out, this is an easy fix - solder a bodge wire to the right hand side of C53, that's the nearest ground plane point. C51 or C52's right hand side will also work.
I'll do a clean export of the sprint original along with the gerbers, put them on GitHub shortly and send this over to Mark @ MacEffects - Revision 1.6b is going to be the CURRENT version, as i've spotted a naming issue with the additional address line tap-point i added for the SMC to do a Classic ROM adapter.
Thank you to everyone for bringing this to my attention - I hate it when issues like this crop up!
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I will say that besides that jumper issue, my Reloaded is doing fine with all other functions!